Manufacturer of Hy-Line trailers.I believe this may be the company you are looking for.
They do make a line of travel trailers that are designed for handicap access. From what I see, their travel trailers seem to be entry level or slightly better quality. They're not very good at giving construction/material specifics. I'd certainly be very cautious and really check their products very thoroughly before purchasing....especially roof construction and potential problems related to water intrusion.